WATERING EPIPHYTAL ORCHIDS
Success or failure with any class of Orchids depends largely on the
exercise of discretion in watering. While it may be said that more
specimens are lost by having too little water, especially among the
smaller-growing species, than by over-watering, at the same time much
mischief is caused by a system of giving a little watering frequently
all the year round, and without any regard to the period of growth or
rest through which the plants are passing. Such treatment does not
provide for strong growth during the growing season, or adequate rest
after the growths are finished; consequently the plants decline in
health and the flowers are not satisfactory. Rain-water is the only
suitable water for Orchids, and the growers who can command a supply of
it all the year round possess a great advantage over those who have to
use water from any other source.
During the period of growth and root action, too much water at the root
cannot easily be given, provided the material in which the plants are
potted is sufficiently porous and the pots or Orchid pans have a
sufficient drainage. The rule should be to water thoroughly when
watering at all, making sure that the whole of the potting material is
moistened well, then not to give more water to that plant until the
effect of the watering is seen to be passing, the plant being still
moist but approaching dryness, when the thorough watering should be
repeated. Nothing is more misleading than to pour a little water each
day on the surface of the material in which the plant is potted. This is
often considered to be careful watering, but it results in a large
number of the plants never getting thoroughly moist at the root, while
others in a retentive compost, or where the drainage is defective,
become soddened. Such cases may arise occasionally under any conditions,
and, where a thoroughly dry plant is found at a season when it should be
moist, it is better to plunge the pot or basket in water until it is
perfectly soaked. In the case of a plant which is too wet with stagnant
moisture, it should either be repotted after the wet potting material
has been removed, or placed on a shelf to remain without water until it
is again in a proper condition to receive it.
In all cases a spouted watering-pot should be used. The rose
watering-pot and syringe are necessary things in the Orchid house, but
the use of them should be rigidly restricted to some definite work, such
as watering Orchids for the first time after repotting, sprinkling the
floors, staging, and brick walls, and other work which cannot cause
mischief. It used to be a common practice to water Orchids overhead with
a rose watering-pot, but the plants so watered made but few roots, and
the foliage was generally unsightly, owing to deposits from the water.
It is therefore best to make a rule against watering overhead in a
general way.
The syringe may be used among Dendrobiums and some other warm-house
Orchids during the height of the growing season; but it would be safer
to arrange for such work to be done by means of a sprayer and at shorter
intervals. The sprayer is a very useful and beneficial contrivance, and,
in the hands of a careful operator using clean rain-water, it affords a
valuable aid in maintaining a healthily humid condition in the
atmosphere of all the Orchid houses, especially during the heat of the
summer.
Equal in importance to the giving of sufficient water during the growing
season is the observance of the dry, resting season, which, in a varying
degree, is required by all Orchids, whether they come from hot or cold
habitats, and whether they are epiphytal or terrestrial species.
WATERING TERRESTRIAL ORCHIDS
These, like the epiphytal Orchids, may be divided into two main classes,
namely, those which lose their leaves annually, and those which are more
or less evergreen. Some of the genera contain both of these classes, and
notably the Calanthes. In _C. vestita_, _C. Regnieri_, _C. rosea_, and
their varieties and hybrids the leaves turn yellow after the growths are
fully made up, a sign which gives a good indication as to the necessity
for withholding water for a lengthened period; while _Calanthe
veratrifolia_ and others of the class retain the last-made foliage green
all the year round, the loss of foliage being in the old leaves, which
should be removed at the first sign of decay. With these latter may be
classed the Phaius, Zygopetalums, Cymbidiums, Cypripediums, and many
others of evergreen habit, which require much care to be exercised in
the matter of withholding water during the resting season, otherwise the
plants will decline in vigour. After the growths are finished, most of
these plants are benefited by removal to a cooler and more freely
ventilated house for a few weeks, during which time the supply of water
should be restricted, but they should never be allowed to suffer by
being thoroughly dried. For Zygopetalums and other Orchids which it is
customary to place in a rather drier atmosphere during the time they are
in flower, such an interval would be sufficient rest.